Sort-of-sticking backhoe boom valve

   / Sort-of-sticking backhoe boom valve #1  
N

ning

Elite Member
Joined
Mar 30, 2017
Messages
2,536
Location
Northern California
Tractor
Branson 3520h
My backhoe (Branson/Ansung BH76) boom valve seemed to be sticking; in operation the valve joystick and operation felt funky.

I searched around and found some ugly pics of rusted springs under the valve, so I took off the cover and briefly considered removing hoses so I could access the valve base before I realized 4 little bolts going into the back of the valve unit from the seating area held the whole thing up.

Removed those 4 and the whole thing just flopped down and I was able to inspect the base.

I found that the bottom springs are in these black enclosures - and the enclosure for this valve was loose and moving with the valve operation, and its bolts were loose. Tightened those two bolts (4mm hex key) and the valve is happy again.

What are those enclosures called, and why does the cover affect the spring action?
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   / Sort-of-sticking backhoe boom valve #2  
Not sure what the correct name is for those covers but on some valves they are used as position stop for the centering spring assembly.
 
   / Sort-of-sticking backhoe boom valve #3  
It is a spool valve cap.

It holds the valve spool centering spring and washer in place.
 
   / Sort-of-sticking backhoe boom valve
  • Thread Starter
#4  
leonz said:
It is a spool valve cap.

It holds the valve spool centering spring and washer in place.
Click to expand...
Sweet, good to know names of things.
Glad to hear that it being loose is a likely source for the symptoms (besides the fact that tightening it down seems to have fixed them).
 
   / Sort-of-sticking backhoe boom valve
  • Thread Starter
#5  
So I'm pretty sure this boom valve is "sticking" because it's a float position lol
 
   / Sort-of-sticking backhoe boom valve #6  
One of my BH's joysticks was sticking and would not travel all the way in one direction. It turned out to be the linkage mechanism under the square rubber dust cover. The linkage translates front/back and side to side motion into pushing the appropriate spools. Water had gotten in there and corroded the aluminum base casting and a small chunk fell out and into the mechanism. I cleaned it up and lubricated the mechanism for both joysticks. Now I get full travel on the one and both of them work better.

I have to store the BH out in the weather. Now I cover both the seat and the valves to keep rain out.
 
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